No family still active in public life has been the subject of more biographical interest than the Kennedys. Their literary charisma is so great, in fact, that no Kennedy life seems unexamined and no publishing season passes without a Kennedy best seller. Now comes The Kennedys, a 700-page, five-generation history written by New York Newsday reporter Thomas Maier. The inevitable question arises: Why is this Kennedy book different from all the rest?

Maier has a ready answer. He has subtitled his book America's Emerald Kings and billed it as the story of "the ultimate Irish-Catholic family." This is a presumptuous claim that no author should be expected to fulfill, but Maier tries anyway, repeating the challenge in his text: "Since their arrival in this land, the Kennedys have been exemplars of the Irish-Catholic experience in America."

One could argue exactly the reverse. Most Kennedy biographers have been impressed by the way the family did not so much exemplify as transcend their ethnic beginnings. "Camelot," for example, which was the Kennedys' self-named moment in the American sun, was an English court, and JFK was himself a noted Anglophile. Maier acknowledges these facts but treats them as extraneous to the story he wants to tell.

Even more problematic for Maier's thesis is the fact that Joseph P. Kennedy, "the founding father" of the Kennedy epic, turned his back on Irish Boston, where his father, P.J. Kennedy, had been a typical ethnic pol. He moved the family seats to WASPy Hyannisport, Mass., and Palm Beach, Fla., directing its aspirations toward such un-Irish horizons as Hollywood, London and Washington. In doing so, he began the process of launching one of the most remarkable (and decidedly un-ethnic) political careers in American history.

Maier's attention to Irish and Catholic themes of this saga is also not original. Doris Kearns Goodwin and other serious Kennedy biographers have paid attention to these elements. The question Maier's book raises is just how much attention is appropriate.

No other biographer has begun a Kennedy narrative, for example, with 34 pages of social history about Ireland, County Wexford and Dunganstown, where the Kennedys' remote ancestors lived. Part of the reason is that we know virtually nothing about these ancestors and only a handful of facts about the Kennedy who came to America in 1848. Nor do we know much about his American son, even though P.J. Kennedy was a powerful Boston politician and Massachusetts legislator whose "story" takes us to Page 50 in Maier's text.

The problem with this material is not that it lacks interest but that it is not particularly connected to the individuals who are the proper subject of the text. The material that is relevant could be summarized in five pages rather than 50. Maier seems to have been more intent on creating a big book with an "original" selling point than on meeting this basic authorial obligation. As a result, his claim that he adds a new dimension to the Kennedy story remains largely unfulfilled, despite his efforts.

Every writer of biographies mourns the moments and the material he or she has unearthed that cannot be included in the work. A biography is not an archive; it is a selective rendering of the facts that is to be judged on how it shapes the story in a way that helps us to understand a life. Large swaths of Maier's hefty text contribute nothing to this understanding.

Why does Sen. Joseph McCarthy merit attention on 19 pages while Teamster boss Jimmy Hoffa - about whose relationship with Bobby Kennedy whole books have been written - merits no mention at all? The answer is the same for all of these examples: McCarthy was Irish-Catholic and the others were not.

Maier's prose sometimes descends to the tabloid, as when he refers to "McCarthy's anti-Red jihad," but a more serious problem is that his journalistic background has not prepared him to penetrate the Kennedy facade to uncover the drama underneath, which is a biographer's primary task. Thus he pads his narrative with discussions of McCarthy's support among Irish Catholics, his adversaries among non-Catholics and the Kennedys' support for him because he was an Irish Catholic. But how does this illuminate the relationship between Bobby Kennedy, the famous liberal, and McCarthy, the famous anti-liberal, or the fact that brother Jack had a more distanced and nuanced attitude toward the senator's crusade than either his brother or father? It doesn't, because the answers to these questions lie in the characters of the individuals, not in their Catholicism. Character is the canvas on which the biographer builds his edifice; it is the key to understanding who the Kennedys were and how they triumphed and failed. But it is precisely in the portrayal of character that Maier's book is lacking.